Pharmacologically active compounds derived from ergotted grain, referred to generically as ergot alkaloids, have been known for centuries. The ergot alkaloids have been shown to possess a wide variety of valuable physiological activities. Almost all of the ergot alkaloids and their derivatives are alike in that they possess the same general tetracyclic ring system represented by the formula ##SPC1##
Ergot alkaloid compounds containing the above ring system are usually classified into one of two classes: those which are amides of D-6-methyl-8-carboxy-.DELTA..sup.9 -ergoline, (lysergic acid); and those which are derivatives of D-6-methyl-8-methyl-.DELTA..sup.8 or .DELTA..sup.9 -ergoline, (the clavines). Typically, compounds of the clavine class possess some degree of prolactin inhibitory activity. Because of this unique activity, these compounds are useful in the treatment of prolactin-dependent conditions in which prolactin secretion has an adverse affect.
Numerous semi-synthetic ergot alkaloid derivatives of the clavine class have recently been prepared and shown to possess useful properties. For example, Camerino et al. prepared and evaluated numerous 8-acylaminomethylergolines, as described in U.S. Pat. No. 3,238,211. Erich et al. prepared a wide variety of 8-acyloxymethylergolines which demonstrated strong uterus-contracting action. Additionally, Arcamone et al. prepared a variety of ergoline derivatives, including 8-acylaminomethylergoline derivatives, see U.S. Pat. No. 3,324,133.
It is an object of this invention to provide new ergot alkaloid compounds characterized as being of the clavine class.